Producing musical tones.



M. L. SEVERY & G. B. SINCLAIR.

PRODUCING MUSICAL TUNES.

APPLICATION FILED 113.19, 1910.

1,009,798. Patnted Nov. 28, 1911.

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PBODTU'CIkG MUSICAL TONES.

Specification of Letters Patent;

Patented Nov. 28, 1911.

To all whom it may concern:

Be it known that we, MELVIN-L. Seven, of Arlington Heights, in thecounty of Middlesex and Commonwealth of Massachusetts, and GEORGE B.SINCLAIR, of Medford, in said county and Commonwealth, both citizens ofthe United States,have invented certain new and useful Improvements inProcesses of Producing Musical Tones, of which the following is aspecification.

Our invention has for its object the production of musical tones inmusical instruments embracing sonorous bodies, and electromagnetic meansfor their actuation;

the especial features of our invention com- Fig.2 is a cross section 0the same. Fig. 3

is a cross section. on a larger scale of a similar means but adapted forcarrying into effect added steps in our process.

In Fig. -.-1 is illustrated a considerable number of sonorous bodies, asstrings 1, which are designed to be tuned to the successive notes of themusical scale. Each strin is provided with an electromagnet2 to w ichelectric pulsations are to .be transmitted for the magnetic actuation ofsuch string; and each electromagnet is inv circuit with a pulsation(producing means, all which means are rotate commensurately with eachother, as by being mounted on a common shaft 3. In previous electricalmusical instruments made by us, as those set forth in our companionapplication No.'443,912, we take a continuous current, from anysuitablesource, and transform the same into pulse tions suitable for the varioustuned sonorous bodies, means of current interrupting devices.

or alternating currents adapted for the dlfierrotors,

ot erwise occur, and consequently dn this process, however, we generatede novo the desired pulsato ent electromagnets and strings. Each suchcurrent generator is hereshown as consisting of. an electromagneticspool having heads 4 'and'windings'v 5,.said windings bein in circuitwith any suitable source as 6, in ig. 2. Said heads are formed withvperipheral teeth 7 which by moving in the fields of the pole pieces 8,induce intermittent or ulsatory alternating currents in the windings 9whlch are immediately shared in by the connected electromagnets 2. I

By having the teeth 7 on the spools, or

far enou h apart, the currentpulsations will have dead intervals betweenthem long enough to permit the strings to recede from theirelectromagnets and be a 21in attracted thereto; but in case the saldteeth are so close together as not to allow such dead intervals, then itis essential to polarize each electromagnet, as illustrated in Fig. 3.One method of such polarization consists in elongating the core of'themagnets 2, and mounting thereon windings 10 wired to a source of directcurrent 11. Then inasmuch as each currentalternation consists of oneflux in onedirection, and another in the re verse direction, one halfofleach alternation will'be of like polarity in the electromagnet' 2 tothat of the windings 10 and W111 double the magnetic efiect of themagnet;

while the other half will beof uirlike polarity, and will neutralize thepolarity of the instance must have a number of teeth 7 1n its I heads 4-whichwill be incommensurate with the number of teeth on the heads 4 ofthe rotor associated with the string C. We sur-.-

mount this difficulty by formin a blank space 12 at the section of theeads per1 hery where the fractional tooth would separate each group ofcorrectly time im ulsegcnerating teeth with an interval di ering cm theremaining teeth. I

As thus far described, our process will consequentl be seen to consistin generating eleotriclty in a multiplicity of pulsations of a frequencyequal to the vibrations of a tuned sonorous body, the pulsations beingseparated into groups by the interposition of an interval differing fromthe vibrational interval of said body. It will also be seen that weimpress upon the electromagnet controlling a tuned sonorous bodyelectric pulsations equal in frequency to the vibrations of such body,and also electric pulsations unequal thereto, the former being so muchmore numerous as to practically overwhelm and.

render negligible the latter pulsations.

in the apparatus illustrated in Fig. 3, we set'forth a process wherebywe superpose upon the electromagnet 2 a plurality of simultaneouslyproduced electric pulsations, and consequently affect its associatedsonorous body 1 with a correspondingly greater strength. In doing thisthe rotor heads 4 are each surrounded by pole pieces 15 equal in numberto the teeth 7 and separated from each other by angular spaces equal tothose between the teeth. These pole pieces are shown as arranged in twogroups, but we do not restrict ourselves to this number, the windings 16of each roup being wired together tandem, but t ey may be wired inmultiple. Inasmuch as when the abnormal space 12 is presented towardeither said group, more or less ofthe pole pieces thereof will not be inphase with juxtaposed teeth, we arrange to cut out of the circuit to theelectromagnet 2 each said group when said abnormal space reaches it, andswitch into the circuit the group from which said space has justdeparted. In this manner we superpose upon the elcctromagnet a number ofsimultaneous current pulsations substantially equal to one half of theteeth. To thus cut in and out said pole piece windings 16, the shaft 3is provided with a semi-circular contact 1'? having in position to touchthe same two oppositely located stationary brushes 18, 19. Each brush iswired to .one terminus of one group of windings 16, while the oppositeterminus of each group is wired to the electromagnet 2; and the shaft 3has a. brush 20 wired to said electromagnet. As the rotor revolves,.said contact 17 automatically cuts out one group of windittgs andswitches in the other group, and so keeps the electromagnet constantlysupplied with vigorous resultant pulsations, separated into groups asshown by phase displacements.

What we claim as our invention and for which we desire Letters Patent isas follows, to

1. The herein described process of educing a musical tone, whichconsists in generating electricity in a multiplicity of series ofrecurrent cycles of pulsations, most of said series of cycles having ineach cycle thereof a plurality of frequencies of pulsations the majorityof said pulsations being in each case of the vibrational frequency of anassociated sonorous body, but the remainder of said pulsations being ofa different frequency and causing said pulsations to vibrate saidsonorous body.

'2. The herein described method of educing a musical tone, whichconsists in generating electricity in cycles of current pulsations, allbut a few of the pulsations of each cycle being equidistant in time eachfrom its preceding and following pulsations, but some thereof beingseparated from certain of their associated ulsations b intervalsdifferent from those intervening etween the majority of said pulsations,and impressing said pulsations upon means adapted to vibrate a sonorousbody.

3. The hereindescribed method of educing a musical tone, which consistsin generating electricity in cycles of impulses most but not all ofwhich im ulses in each of most of the cycles are equidistant from eachother in point of time, and impressing said impulses upon means adaptedto vibrate a sonorous body.

4. The herein described method of educing a musical tone, which consistsin generating electricity in a plurality of trains of impulsesall but afew of the impulses in each train being equidistant from each other inpoint of time and the impulses of some trains eing of a frequency perunit of time incommensurate with that of some of the other trains, thesaid trains being generated b rotary motions commensurate with eachother, and impressing said impulses upon means adapted to vibrate asonorous body.

5. The herein described method of educing a musical tone which consistsin generating a plurality of series of electric impulses,

some of the alternations in some of the series being out of tunerelative to their neighboring impulses, each said series havin a.majority of its impulses timed to the vibrations of a note of themusical scale and the frequencies of the majority of the impulsescomposing some of the series being incommensurate with the frequenciesof a majority of the impulsescomposmg some of the other series, andimpressing said impulses at will Epm means adapted to vibrate a sonorous6. The herein described process of producinga musical tone, whichconsists in generating electricity in pulsations equal in frequency tothe vibrations of a sonorous body, and also generating other electricalpulsations of a different frequency, and impressing both kinds ofpulsations upon said sonorous body, the proportion of the first namedpulsations being in suiiicient excess over that of the other pulsationsas to overpower them and render negligible their effect.

7. The herein described process of educing a musical tone, whichconsists in generating electricity in a multiplicity of pulsations of afrequency equal to the vibrational frequency of a sonorous body, thesaid pulsainvention, We have hereunto set our hands tions beingseparated into groups by the inthis 27th day of January, 1910.terposition of an in erval differing from the M ICLVIN L. SEVERY.vibrational intervals of said sonorous body, GEORGE B. SINCLAIR. 5 andutilizing the said pulsations to vibrate \Vilnessvs:

said sonorous body. A. B. UIIL-Ul,

In testimony that we claim the foregoing ,nAmncs GARRISON.

